Various composition targets, which are also known as "clay pigeons," are used for trap and skeet shooting. These targets have generally been made in the form of saucer-shaped structures which are molded from suitable mixtures, and most of the commercial targets include petroleum or coal tar pitch as the binder, along with a filler material such as clay or other finely divided minerals, such as limestone, so as to provide a relatively fragile or frangible structure.
These targets are intended to be used by marksmen in such trap and skeet shooting, and therefore must be capable of not only being projected for considerable distances, but must also be capable of disintegrating upon contact with a pellet or pellets and withstand the vigorous action of the trap required to propel the target into the air. If this is not the case, the target will not indicate when the marksman has scored a hit on the target, i.e., unless the target is entirely frangible and shatters upon impact.
In addition, since trap shooting is generally conducted out of doors, where the targets then shatter and fall to earth, environmental acceptability has become a particularly sensitive problem. The shattered targets are thus potentiall eaten by birds and other wild or domesticated animals, and indeed this problem is particularly acute in connection with hogs, which are thus the subject of specific warnings printed on the packing cases for many conventional targets. Furthermore, unless these targets are entirely acceptable from an environmental viewpoint, they can cause many other types of pollution.
Finally, in view of their very nature, it is also essential that these targets be produced at the cheapest possible cost per target, therefore requiring materials of construction which have the most nominal of costs associated with them.
Among the earliest developments in this field were glass balls and the like, which were initially used as targets as shown in U.S. Pat. No. 222,301. In this patent, substitutes for such glass balls are shown, including sodium and potassium silicate targets, which are said to be usable in admixture with a small percentage of sodium carbonate or hydrate and which are employed by melting these components and producing a "soluble glass" target therefrom.
As this art developed, targets were produced from various compositions, including finely divided clay mixed with water, which was then molded and kiln dried. Other materials used were plaster of Paris, sand and pitch, all of which, however, suffered from the various deficiencies discussed above.
At the present time, the most popular composition target in use is one consisting of a composition of ground limestone and pitch, such as is disclosed in U.S. Pat. Nos. 2,831,778 and 3,399,255. Such targets, however, are not only relatively expensive, since pitch has an elevated price structure and requires a rather large energy consumption in manufacturing processes utilizing same, but they are also toxic, very susceptible to changes in temperature, and do not shatter with the proper degree of consistency at various temperatures. Such targets are not environmentally degradable, thereby causing serious concern with respect to the environment, and the possibility of harm to animal life, particularly hogs, as discussed above. Targets have also been produced from sulfur, and sulfur combined with various additives, in an attempt to replace the conventional pitch and limestone or clay targets. Thus, in Canadian Pat. No. 959,203 and U.S. Pat. No. 3,884,470 the patentee discusses such a sulfur target composition, which in that case is made by melting the sulfur composition and injection molding the targets therefrom.
Further improvements in such targets have also been attempted, such as that in U.S. Pat. No. 3,840,232, in which targets are molded from mixtures of elemental sulfur and limestone dust as an inert filler. These targets are produced by initially heating to produce a fluid mix, and then molding. The inclusion of materials such as bentonite clay, which are materially unstable in the presence of water, are also disclosed as producing environmentally degradable targets in that environment.
Finally, other attempts have been made to produce targets from synthetic materials, such as those in Japanese Pat. No. 52-48300, which includes low molecular weight thermoplastic resins such as polystyrene, along with high molecular weight thermoplastic resins such as polyethylene, in combination with inorganic fillers such as calcium carbonate, clay, etc., and U.S. Pat. No. 3,554,552 in which such targets are produced from compositions of polystyrene and polyethylene waxes.
Yet another approach to the production of such targets while at the same time reducing the amount of pitch present as a binder therein, is set forth in a series of patents to Moehlman et al, namely U.S. Pat. Nos. 3,399,255; 3,376,040; and 3,577,251. In these patents, a process for reducing the pitch content of these targets is set forth in which, in various embodiments, specific procedures are employed in order to coat the inert filler or limestone component with pitch or tar, and to then compression mold targets therefrom. In this manner, the patentee attempts to reduce the pitch content down to between about 8 and 25 percent thereof.
It is therefore an object of the present invention to overcome these deficiencies of the prior art, and to thus produce a frangible, projectable target which does not suffer from the disadvantages of these prior art targets. In particular, it is an object of this invention to produce such a target easily and economically, from materials which are far less expensive than those previously utilized.